The present invention relates to a sports ball; in particular, the invention relates to a sports ball used for such sports as volleyball, basketball, dodgeball, soccer, or handball.
Hitherto, sports balls are produced by two methods. A first type of conventional ball is produced, for example, by pumping air into an inflatable tube and affixing cloth pieces closely on the surface of the tube with latex, or by winding a string around the surface of the tube and fixing the string on the surface with an adhesive agent to form a reinforced layer, followed by the adhesion of the outer layer. A second type of conventional ball is produced by the following steps, for example, as disclosed in a Japanese Patent Application, First publication, Sho 58-29112. Cloth pieces are attached on the surface of an empty globe which consists of brittle material such as paraffin to form a cloth pouch. The globe is removed from the pouch and an inflatable tube is put into the pouch. The tube is filled with air and protruding bars are formed on the alignments which are formed on mutually overlapping cloth pieces. Then, an outer layer is attached on the surface of the pouch along the bars.
The first type of conventional ball has the desirable characteristic of high strength because the tube is protected by a reinforced layer which is located exterior to the tube. The second type of conventional ball has the advantage of durability because a space is provided between an inner surface of the pouch and an outer surface of the tube, so this ball may absorb stresses caused by external forces.
However, the first type of conventional ball is relatively hard and inferior in softness. The second type of conventional ball is superior in softness, although production efficiency is low and it is expensive because it requires complex production steps such as: forming an empty globe consisting of brittle material, attaching cloth pieces on the surface of the globe to form a cloth pouch, and removing the globe from the pouch.